From patchwork Mon Aug 29 02:37:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hou Tao X-Patchwork-Id: 12957402 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 916F3C0502A for ; Mon, 29 Aug 2022 02:19:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229455AbiH2CTI (ORCPT ); Sun, 28 Aug 2022 22:19:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57694 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229379AbiH2CTH (ORCPT ); Sun, 28 Aug 2022 22:19:07 -0400 Received: from dggsgout12.his.huawei.com (unknown [45.249.212.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B63953C17A for ; Sun, 28 Aug 2022 19:19:05 -0700 (PDT) Received: from mail02.huawei.com (unknown [172.30.67.143]) by dggsgout12.his.huawei.com (SkyGuard) with ESMTP id 4MGDbn4qw6z6S2rG for ; Mon, 29 Aug 2022 10:17:25 +0800 (CST) Received: from huaweicloud.com (unknown [10.175.124.27]) by APP2 (Coremail) with SMTP id Syh0CgAnenMTIgxjzJZKAA--.51878S4; Mon, 29 Aug 2022 10:19:01 +0800 (CST) From: Hou Tao To: bpf@vger.kernel.org Cc: Song Liu , Sebastian Andrzej Siewior , Thomas Gleixner , Hao Sun , Hao Luo , Andrii Nakryiko , Yonghong Song , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , KP Singh , "David S . Miller" , Jakub Kicinski , Stanislav Fomichev , Jiri Olsa , John Fastabend , Lorenz Bauer , houtao1@huawei.com Subject: [PATCH bpf-next v3 0/3] fixes for concurrent htab updates Date: Mon, 29 Aug 2022 10:37:06 +0800 Message-Id: <20220829023709.1958204-1-houtao@huaweicloud.com> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 X-CM-TRANSID: Syh0CgAnenMTIgxjzJZKAA--.51878S4 X-Coremail-Antispam: 1UD129KBjvJXoW7urW8JryxWr4DCFW5Ww15urg_yoW8tF1rpa yxW3W5Kw1xtrnFqw47tw1j9FWFya1rGr4jkrn3W3y5Z3yUKFyxZr4I9r4rZrs5KrZ3Wryf Ar4xtFs5Za18ZrDanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUkIb4IE77IF4wAFF20E14v26ryj6rWUM7CY07I20VC2zVCF04k2 6cxKx2IYs7xG6r1S6rWUM7CIcVAFz4kK6r1j6r18M28lY4IEw2IIxxk0rwA2F7IY1VAKz4 vEj48ve4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_tr0E3s1l84ACjcxK6xIIjxv20xvEc7Cj xVAFwI0_Gr1j6F4UJwA2z4x0Y4vEx4A2jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x 0267AKxVW0oVCq3wAS0I0E0xvYzxvE52x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG 6I80ewAv7VC0I7IYx2IY67AKxVWUJVWUGwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFV Cjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI48JM4IIrI8v6xkF7I0E8cxan2IY04v7MxAIw28I cxkI7VAKI48JMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2 IqxVCjr7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVW8ZVWrXwCIc40Y0x0EwIxGrwCI 42IY6xIIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42 IY6xAIw20EY4v20xvaj40_Wr1j6rW3Jr1lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2 z280aVCY1x0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7IU13rcDUUUUU== X-CM-SenderInfo: xkrx3t3r6k3tpzhluzxrxghudrp/ X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Hou Tao Hi, The patchset aims to fix the issues found during investigating the syzkaller problem reported in [0]. It seems that the concurrent updates to the same hash-table bucket may fail as shown in patch 1. Patch 1 uses preempt_disable() to fix the problem for htab_use_raw_lock() case. For !htab_use_raw_lock() case, the problem is left to "BPF specific memory allocator" patchset [1] in which !htab_use_raw_lock() will be removed. Patch 2 fixes the out-of-bound memory read problem reported in [0]. The problem has the root cause as patch 1 and it is fixed by handling -EBUSY from htab_lock_bucket() correctly. Patch 3 add two cases for hash-table update: one for the reentrancy of bpf_map_update_elem(), and another one for concurrent updates of the same hash-table bucket. Comments are always welcome. Regards, Tao [0]: https://lore.kernel.org/bpf/CACkBjsbuxaR6cv0kXJoVnBfL9ZJXjjoUcMpw_Ogc313jSrg14A@mail.gmail.com/ [1]: https://lore.kernel.org/bpf/20220819214232.18784-1-alexei.starovoitov@gmail.com/ Change Log: v3: * patch 1: update commit message and add Fixes tag * patch 2: add Fixes tag * patch 3: elaborate the description of test cases v2: https://lore.kernel.org/bpf/bd60ef93-1c6a-2db2-557d-b09b92ad22bd@huaweicloud.com/ * Note the fix is for CONFIG_PREEMPT case in commit message and add Reviewed-by tag for patch 1 * Drop patch "bpf: Allow normally concurrent map updates for !htab_use_raw_lock() case" * Add two test cases for htab updates v1: https://lore.kernel.org/bpf/20220821033223.2598791-1-houtao@huaweicloud.com/ Hou Tao (3): bpf: Disable preemption when increasing per-cpu map_locked bpf: Propagate error from htab_lock_bucket() to userspace selftests/bpf: add test cases for htab update kernel/bpf/hashtab.c | 30 ++++- .../selftests/bpf/prog_tests/htab_update.c | 126 ++++++++++++++++++ .../testing/selftests/bpf/progs/htab_update.c | 29 ++++ 3 files changed, 178 insertions(+), 7 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/htab_update.c create mode 100644 tools/testing/selftests/bpf/progs/htab_update.c